The present invention relates to a method for fine patterning of a polymeric film in a novel procedure not known in the prior art to obtain a patterned polymeric film which can serve as an etching resist in an etching treatment of a substrate surface.
As is well known, the manufacturing process of various kinds of electronic parts including semiconductor devices, e.g., ICs and LSIs, involves a step of fine patterning of the substrate surface which is performed by the photolithography, electron-beam lithography, X-ray lithography and the like. Each of these lithographic methods utilizing actinic rays as the patterning means has its own disadvantages and limitations. For example, the photolithographic method has an inherent limitation in principle that the fineness of the pattern formed thereby can hardly be finer than a half of the wavelength of the light, e.g., ultraviolet light, used for pattern-wise irradiation of the resist layer. In the X-ray lithography, pattern resolution in the order of 10 nm has not yet been accomplished because the fineness of an X-ray mask for patterning currently available is not so high. Pattern resolution of 10 nm order cannot be obtained also in the electron-beam lithography due to the limitation in the resolving performance of the resist material per se or due to the influences of scattering of the secondary electrons. In addition, there is a problem that the method is considerably time-consuming because the method is performed by scanning of an electron beam in accordance with the desired pattern. This problem is particularly serious when a patterned resist layer including a large number of fine structures of the nanometer range, such as a large number of quantum dots.